1. Field of the Invention
This invention relates generally to fingerprint sensors and related devices and, more specifically, to a Flash-interfaced Fingerprint Sensor.
2. Description of Related Art
Miniature portable electronic storage devices have advanced substantially in recent years. An extremely popular version is the USB flash drive. FIG. 1 is an exploded perspective view of a conventional USB flash drive 10. The Conventional USB Flash Drive 10, which many times is configured to be attached to a person's keychain, is roughly the size of a package of gum and is defined by a Housing 12 from which a USB Plug 14 extends, with a Cap 16 typically included to protect the Plug 14. This Conventional Drive 10 is used generally to permit the easy storing and transfer of electronic files. The user simply inserts the USB Plug 14 into the appropriate receptacle on a host computer and the computer's operating system generally will discover the new addition and will then allow the user to access the memory on the Flash Drive 10 just as the user would access any other storage device associated with the computer. If we now turn to FIG. 2, we can examine the main components of the Conventional Flash Drive 10.
FIG. 2 is a block diagram of the conventional USB flash drive of FIG. 1. Within the Housing 12 is a Circuit Substrate 20, which is typically a conventional PC board. On the Circuit Substrate 20 a plurality of Flash Memory Devices 24 are attached and electrically connected. A Flash Interface Device 22 controls access to the Memory Devices 24 by the External Computing Device 18 such as a host personal computer.
The Flash Memory Devices 24 are available in different sizes, and furthermore the number of Devices 24 included in the Flash Drive 10 can be varied in order to provide the amount of memory that is desired by the manufacturer. Turning to FIG. 3, we can examine how the Flash Drive 10 operates.
FIG. 3 depicts the functional orientation of the drive of FIGS. 1 and 2 relative to a host computing device. As shown here, there are four Flash Memory Devices 24A, 24B, 24C and 24D. Each of these Devices 24 communicates directly with the USB Flash Interface Device 22. The Interface Device 22 is designed to control access to the Memory Devices 24 from any outside system. The Device 22 may include the ability to encrypt and/or password protect access to the Memory Devices 24. The USB Flash Interface Device 22 then communicates with the USB Host Interface Device 26 that is contained within the External Computing Device 18. Within the Computing Device 18 there will also be Driver Software Applications 28 that enable the functionality of the USB Flash Drive 10, including some encryption and/or password protection capabilities associated with the USB Flash Interface Device 22.
In an effort to further secure the data contained within the Conventional USB Flash Drive, one manufacturer incorporated a Fingerprint Sensor Device 32. FIG. 4 depicts a system incorporating this device. FIG. 4 is a block diagram of a conventional fingerprint-sensing USB flash drive 30. The Conventional Fingerprint Sensing USB Flash Drive 30 comprises a Housing and USB Flash Interface, but in this case the Flash Interface Device 23 has specialized capabilities in order to enable it to interface with the Microcontroller Fingerprint Sensor Device 32 that is used in this Drive 30. Furthermore, because the Fingerprint Sensor Device 32 and Specialized Flash Interface Device 23 would otherwise be an incompatible with the conventional circuit substrate, a Specialized Circuit Substrate 21 must be used for this Fingerprint Sensing USB Flash Drive 30.
The Microcontroller Fingerprint Sensor Device 32 has two main parts; the Fingerprint Sensor System 34 and the Microcontroller Interface 36. If we now turn to FIG. 5, we can discuss the operation of this Drive 30.
FIG. 5 depicts the functional orientation of the drive of FIG. 4 relative to a host computing device. As shown here, each of the Flash Memory Devices 24, rather than communicating directly with the USB Flash Interface Device 23, instead communicate directly with the Microcontroller Fingerprint Sensor Device 32. Specifically, the Microcontroller Interface portion 36 of the Device 32 operates to accept fingerprints that are sensed by the Sensor System 34 and then determine whether or not access will be granted to the Devices 24 via the USB Flash Interface 23. If access is granted, then the USB Host Interface 26 will be allowed access and the Driver Applications 28 will also be allowed to access to the Flash Memory Devices 24.
The problem with this prior system is that it is so customized in its design, that beyond the conventional flash memory devices, virtually every component within the drive is custom. As a result, this device can never be cost competitive with a non-fingerprint sensing USB drive and furthermore is unlikely to be economically feasible. What is needed is a low-cost way of converting conventional USB flash drive architecture to add fingerprint sensing capability.